Gambia's Interior Ministry announced on Monday that nine criminals had been killed by a firing squad the day before. All of those who received the death penalty had lost their respective final appeals.

The U.S. State Department has called upon on President Jammeh to "immediately halt all executions."

Many critics are calling into question the transparency and impartiality of the executions as well. Christof Heyns, the U.N. special rapporteur on extrajudicial, summary or arbitrary executions, noted that, "according to available evidence, the trials did not meet due process safeguards." He added that "the executions were carried out in secrecy, away from the public and from the families, and do not meet the requirements of transparency."

Despite the heavy-handed international criticism, Gambian leaders are not backing down. "Every sovereign state has its own national laws, which may be different from other countries, and in the case of the Gambia, the sentences that were handed out were in due compliance with the laws of the country," Jammeh said in a statement.

The efficacy of capital punishment as a deterrent for criminal activity is still a hotly debated topic. In its argument against the death penalty, Amnesty International cites a 2009 survey of criminologists which revealed that over 88 percent believed the death penalty was not an effective deterrent to murder.